Earlier this week, an administrative hearing was conducted in Prescott to address challenges to the recent AZ Dept. of Water Resources (ADWR) ruling that gave Prescott permission to pump just over 8,000 acre-feet per year from the Big Chino basin to supplement water use in Prescott and Prescott Valley.
The local paper up there covered the hearing with daily reports that can be found here, here, and here. I wasn't at the hearing myself so this post is based on those reports plus my own knowledge of the situation up there.
ADWR's decision effectively increases the amount of the Prescott area's Assured Water Supply designation, permitting increased development in the area. One of the big complaints presented by objectors was that the Prescott Active Management Area (AMA) that includes Prescott, Prescott Valley, and some of Chino Valley is currently overdrafted and most knowledgeable people will admit that they have almost no real chance of getting to safe yield (where water going into the aquifer equals water going out), which is the eventual management goal for the AMA. Therefore, why should Prescott be permitted to use this water to support future growth - they should be using it to achieve safe yield by putting it into the aquifer. The fact that they would be mining a nearby aquifer in order to put the water into their own aquifer is irrelevant on this issue - this is Arizona groundwater law after all.
But the big issue in this hearing is basically whether Prescott should be permitted to pump water from the Big Chino aquifer, which is widely considered to be the main source of baseflow for the upper reaches of the Verde River. The upper Verde is a beautiful and bountiful,free-flowing desert river system that elicits strong emotions from its supporters. The Verde River also happens to be one of the main surface water sources for Salt River Project (SRP). SRP is kind of the 800 lb gorilla of water disputes in Arizona. They possess rights to a significant percentage of the surface water found in the state and they do not take kindly to any action within the watershed that could be seen as threatening those rights. Under Arizona law, the connection between groundwater and surface water is tenuous at best, governed by the concept of "subflow." The basic idea behind subflow is that only groundwater found immediately adjacent to a stream (i.e. the streambed itself) has any connection to surface water. All other groundwater in aquifers near a stream and likely providing some contribution to baseflow, but in a more tenuous and hard-to-define manner, is legally distinct from surface water. So a groundwater pumper might dry up a river - as they have with many of Arizona's rivers - and have no liability to surface water right holders who can no longer divert from the river.
The parties have been arguing whether the pumping by Prescott will impact flows in the upper Verde, with one side saying "yes it definitely will" and the other saying "no chance of impact from this pumping." If you ask any decent hydrogeologist (who isn't working for a party in this case) about it they will tell you: it's not a question of "if" the pumping will affect the river, but a question of "when" and "how much." Just take a look at John Bredehoeft's paper, "The Water Budget Myth" and tell me how you balance out inputs and outputs when one side of the equation changes. Prescott is proposing to pump from the aquifer 20 miles from the springs that feed the headwaters to the Verde. So it will probably take some time before effects are seen from their pumping, and those effects might be very small initially. There is a lot of hydrologic uncertainty to the "when" and "how much" questions - the role of geologic structures and heterogeneity in the aquifer to start with - but the "if" question is an easy one.
Prescott has complained loudly in the administrative hearing that some of the local objectors who presented evidence against permitting the pumping are simply straw men for SRP, which was denied the right to participate directly in the hearing because they do not "reside" within the AMA - only entities within the AMA boundaries are permitted to challenge the ruling under state law.
There is going to be more on this process, as the hearing was not completed this week (as noted in the last article), so it will be continued at a later date. Also, once the administrative law judge issues his ruling after this hearing, it can be appealed and moved to the regular court system. And it surely will as long as SRP has a stake in it.
2/17/09: came across this today. If you are interested in more info about the property in Big Chino Valley from which Prescott plans to pump the water, the City of Prescott provides a very basic overview here.
2/27/09: One of the attorneys for SRP told me the hearing is scheduled to continue in April with 3 more days of testimony. Also, it sounds pretty certain that if Prescott gets a favorable ruling from the ALJ (which becomes a recommendation to the director of ADWR to affirm his initial ruling) there will be an appeal in Superior Court. This process will be going on for several years, in other words.